Generally speaking, the conveyor frame is of a rolling shaft type or ball type. The conveyor frame of the rolling shaft type provides the one-dimensional and linear motion; nevertheless it is capable of providing an article with a wider support area. The conveyor frame of the ball type is capable of providing the rolling motion in various directions as well as the multi-dimensional planar motion. However, the ball-type conveyor frame provides the article with a point contact support. As far as these two types of the conveyor frames are concerned, they have advantages and disadvantages.
The Taiwan Utility Patent No. 81202836 discloses a conveyor frame having a support which is provided with a rolling shaft conveying structure and a ball conveying structure. The operator may choose to use either the rolling shaft conveying structure or the ball conveying structure, depending on the need of the operation. The disclosure has a rotary platform on which a rolling shaft conveying structure and a ball conveying structure are pivotally mounted. The rotary platform is pivoted to a cross seat by two side pieces which are provided in the inner walls thereof with a confining block corresponding to the inside of the cross seat. The rotary platform turns on the pivoting point such that the confining block presses against the top of the cross seat, and that the rotary platform is capable of a 90-degree rotation. This structure is defective in design in that the rotary platform is located by the confining block, and that the rotary platform is apt to sway when a cumbersome article is being conveyed.